Valve tappet and method of forming the same



y 1931- I w. c. OSTERHOLM 1,805,255

VALVE TAPPET AND METHOD OF FORMING THE SAME Original Filed April 21,1924 M M 5 a W 5 6/ W a )J 2 If u Patented May 12, 1931 entree WILLIAMG. OSTEBI-IQLM, OF GAK PARK, Z'LLINOIS, ASSIGNGR T0 'WILCOX PRODUCTSCORPORATION, OF BETBOET, MICHIGAN, A COEP-JRATION OF IJIICHIGAN VALVETAPPE'I 5333B METEZGD GE FQRMING THE SAIdE The invention relates to themanufacture of valves, valve tappets and the like wherein the head andstem are formed of separate members which are united to form a singlestructure having properties particularly adapting the same for use ininternal combustion engines. The primary objects of the invention are toreduce the cost of manufacture and obtain a light and durable structure.This application is a division of my co-pending application, Serial No.708,048, filed April 21, 192d.

In the drawings:

Figure 1 illustrates the head of a tappet as formed by casting, forgingor pressing.

Figure 2 shows the head after a subsequent operation.

Figure 3 illustrates one method of uniting the head and stem.

Figure 4: represents the finished tappets.

Figure 5 illustrates a modified method of uniting the head and stem.

The head is formed in any suitable manner to provide the structureillustrated in Figure 2 and is preferably made from a suitable materialwhich can subsequently be heat treated to form a hard wearing surface.The shape of the head is such that it can be manufactured at a very lowcost as a product of a screw machine and it may either be machineddirectly from a round disk blank of metal or formed to the approximateshape by forging, stamping or casting operations.

Figure 1 shows aforging or casting having a fiat bottom surface 13. Theupper surface of the blank has a cup shaped recess 0 in the centralportion thereof and an annular flange D spaced from and surrounding thecentral portion forming an annular recess E therebetween. The flange 1)extends parallel to the axis of the blank and projects beyond the otherportions of the head, the inner and outer surfaces F and G respectivelybeing slightly tapered corresponding to the requirements for draft in aforging product. The inner boundary of the recess E is formed by thesurface H which is substantially conical in form increasing in diameterfrom the central cup shaped portion toward the bottom of the recess. Thehead preferably,

Original application filed April 21, 1924, Serial No. 708,048. Dividedand this application filed December erial No. 157,347.

although not necessarily, is provided with a flange 1 of uniformthickness projecting radially outward beyond the flange D.

Figure 2 shows the head A as above described after the flange D has beenpressed inwardly. The recess E is now bounded by the annular surfaces Hand F which are substantially parallel forming a slot of uniform widthextending into the head at aninclination to the axis of the same.

The stem J may be formed in various sizes but is pre'erably a tubularmember having the lower end portion K of uniform diameter correspondingto the diameter of the entrance end of the annular slot E in the head A.The opposite end of the stem is shaped to conform with the particularrequirements of the article and as shown is pressed or otherwisefashioned into a polygonal form as indicated at L to produce a wrenchhold. Preferably a bore M of smaller diameter than the main portion ofthe tubular stem extends through the wrench hold portion L and this isthreaded at N to receive the cooperating member of the valve mechanism.

in order to unite the head and stem into a single structure the tubularend K of the stem is inserted into the annular recess E and endwisepressure is exerted on the parts which results in the outward turning ofthe tubular end and the expanding of the diameter so that the tubularmember is forced into the bottom of the recess E. This forms a structureas illustrated in Figure l, in which the stem and head are firmly unitedin interlocking engagement.

Another method of forming the tappet consists in applying endwisepressure to the stem member while it is in registration with the slot Ein the blank shown in Figure 1, this method being illustrated in Figure5. As a result the end of the tubular member is flared outwardly intoconformity with the conical surface H while the annular flange D remainssubstantially parallel to the axis of the head. While the parts areengaged in this manner the flange D is then turned inwardly by applyinginward pressure thereto, thus inclosing the flared end of the stem asshown in dotted lines in Figure 5.

The tappet or other similar article formed by either of the abovemethods is represented in its final form by Figure 4 and it is to benoted that the inter-locking engagement is obtained by a flaring tubularend being in engagement with a recess, the bounding walls of which aresubstantially parallel and oblique to the axis of the head. Where theproduct is to be used as a valve tappet, it is preferable to provide thehead with a central bore 0 through which oil may be fed directly on tothe cooperating cam.

Vhat I claim as my invention is:

1. The method of manufacturing tappets and the like comprising theforming of a head with an annular recess therein bounded on the innerside by aconical surface, said head member having an annular flangeextending substantially parallel to the aXis of said head and formingthe outer side of said recess, the forming of a separate tubular stemmember, theend portion of which is of uniform diameter, applying endwise pressure to said head and stem to flare the end of said tubularmember and conform the same to said conical surface, and pressing saidannular flange inwardly to turn the same into such frictionalinter-locking engagement with said flared tubular end as to preventrotation of said head and stem.

2. A tappet or similar article comprising a head member having anannular recess therein bounded by an inner conical surface and an outersurface substantially parallel to said inner surface, and a tubular stemmemberhaving an end portion terminating in a conical outwardly flaredportion, said flared poition being inserted in said annular recess intonon-rotatable frictional interlocking engagement with the inner andouter surfaces of said recess.

3. A tappet comprising a head having a central cupped portion and anannular flange spaced from said central portion forming an annularrecess inclined to the axis of said head and bounded by substantiallyparallel walls, a separate tubular stem member having an end portionterminating in an outwardly flared conical portion inserted in saidannular recess and in non-rotatable frictional engagement with theparallel walls aforesaid and also in engagement with the bottom of saidrecess and an annular flange projecting radially outward in a directiontransverse to theaxis of said tappet, the lowersurface of said headbeing substantially flat.

4. A tappet comprising a head member having an annular recess thereinbounded by substantially parallel inner and outer surfaces, saidrecessextending into said head in a direction obliqueto the axisthereof, said head being heat treatedto form a hard wearing surface, anda separate tubular stem member having an end portion terminating in aconical flared portion inserted in said recess and in non-rotatablefrictional interlocking engagement with said head.

5. A tappet comprising a head member having an annular recess thereinbounded by substantially parallel inner and outer sun faces, said recessextending into said head, in a direction oblique to the axis thereof andterminating at one end at the surface of said head, and a separatetubular stem member having an end portion terminating in a conicalflared portion inserted in said recess in non-rotatable frictionalengagement with the parallel walls thereof and with the bottom of saidrecess.

6. The method of manufacturing a tappet which consists in forming a headwith a recess therein bounded by inner and outer walls, forming aseparate tubular stem memher, the end portion of which is of uniformdiameter, inserting the end of said stein member in said recess whileflaring the same to cause the same to conform in shape to one wall ofthe recess, and bendingthe-other wall of the said recess to causethesame to frictionally grip the flared end of the said stem member.

In testimony whereof I aflix my signature.

WILLIAM G. os'rERI-roLM.

